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  Low noise tireUSPTO Application #: 20070017619Title: Low noise tire Abstract: A pneumatic tire of which tread portion is curved so that a tread face has a radius of curvature in a range of from 50 to 220 mm, is provided with a noise damper. The noise damper having a joint surface adhered to the radially inner face of the tread portion, is provided with one of the following three designs: (1) the joint surface is curved to fit to the radially inner face of the tread portion and has a width; (2) the joint surface is substantially straight and has a width not more than 30 % of the width of the tread face measured along the tread face; and (3) the joint surface is substantially straight and has a width more than 30% of the width of the tread face measured along the tread face, and each side edge of the noise damper is provided along the length thereof with notches. (end of abstract) Agent: Birch Stewart Kolasch & Birch - Falls Church, VA, US Inventor: Naoki Yukawa USPTO Applicaton #: 20070017619 - Class: 152450000 (USPTO) Related Patent Categories: Resilient Tires And Wheels, Tires, Resilient, Pneumatic Tire Or Inner Tube The Patent Description & Claims data below is from USPTO Patent Application 20070017619. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The present invention relates to a low noise pneumatic tire, more particularly to a combination of a pneumatic tire with a round tread profile and a noise damper adhered to the radially inner face of the tread portion. [0002] In general, motor-cross motorcycle tires are provided with tread patterns having large negative ratio based on tread blocks and/or lugs, and inevitably, a large tire noise is generated during running on the well paved roads. Further, the engine noise of the motor-cross motorcycles is usually large. Therefore, a demand for low-noise tires is scarce in this tire category. [0003] In the case of street motorcycle tires, however, the demand for low-noise tires is increasing because motorcycles such as so called "big scooter" of which engine noise, mechanical noise and wind noise are reduced like a passenger car become popular in recent years. [0004] When compared with the motor-cross motorcycle tires, the street motorcycle tires have relatively small negative ratios, in other words, the tread face is relatively smooth. Accordingly, the tire noise during running on the well paved roads becomes smaller by nature. Despite such a low-noise nature, the tires sometimes generate a large noise at a certain running speed as shown in FIG. 10. [0005] As a result of investigation, it was found that the main cause of the large noise is a resonance of air in the tire cavity of a rear tire. In the case of tires used in the investigation, the noise became increased when the frequency (645 Hz) of the 3rd-order resonance became near the primary frequency of tire vibration during running at a certain speed (105 km/hour) which primary frequency is varied by the running speed, depending on the tread pattern pitches. [0006] In the passenger car tire art, it is known to be effective for reducing the tire cavity resonance to dispose a noise damper in the tire cavity, for example, as disclosed in U.S. Pat. No. 6,726,289. [0007] In the case of motorcycle tires, the tread portion is curved with a relatively small radius when compared with the passenger car tires, and the inner face of the tread portion has accordingly a small radius of curvature in the tire meridian section. Therefore, when adhering such a damper to the inner face of the tread portion, the damper especially the edge portion thereof is very liable to get out of order, and as the width of the damper increases, the rate of occurrence of wrinkles increases. Thus, the durability as well as commercial value is decreased. Further, the efficiency of the adhesion work tends to be lowered. [0008] It is therefore, an object of the present invention to provide a noise damper which is easy to adhere to the curved tread portion's inner face in good order and thus suitable for motorcycle tires, and also a low-noise pneumatic tire with a noise damper in which the durability of the noise damper and the commercial value of the tire can be improved. [0009] According to one aspect of the present invention, a pneumatic tire comprises a tread portion which is curved so that a tread face has a radius of curvature in a range of from 50 to 220 mm, and a noise damper has a joint surface to be adhered to the radially inner face of the tread portion, the noise damper made of a flexible material having a specific gravity of 0.005 to 0.060 and a length substantially equal to the inner circumference of the tire, wherein [0010] the noise damper provided with one of the following three designs: (1) the joint surface is curved to fit to the radially inner face of the tread portion and has a width; (2) the joint surface is substantially straight and has a width not more than 30% of the width of the tread face measured along the tread face; and (3) the joint surface is substantially straight and has a width more than 30% of the width of the tread face measured along the tread face, and each side edge of the noise damper is provided along the length thereof with notches, and [0011] the noise damper has a thickness not more than the width. [0012] Therefore, the noise damper can be easily adhered to the inner face of the curved tread portion in good order without wrinkle, and thus deterioration of the damper durability and degrading of the tire commercial value can be prevented. [0013] Embodiments of the present invention will now be described in detail in conjunction with the accompanying drawings, in which: [0014] FIG. 1 is a cross sectional view of an assembly of a motorcycle tire and a noise damper according to the present invention; [0015] FIG. 2 is a cross sectional view of the noise damper in its stress-free state; [0016] FIG. 3 is a cross sectional view of another example of the noise damper according to the present invention in its stress-free state; [0017] FIG. 4 is a cross sectional view of still another example of the noise damper according to the present invention in its. stress-free state; [0018] FIG. 5 is a cross sectional view of yet still more example of the noise damper according to the present invention in its stress-free state; [0019] FIG. 6 is a cross sectional view of the assembly shown in FIG. 1 taken along the tire equatorial plane showing an example of the arrangement of the circumferential ends of the noise damper; [0020] FIG. 7 is an enlarged cross sectional view showing a carrier type double-sided adhesive tape; [0021] FIG. 8 is an enlarged cross sectional view showing a transfer type double-sided adhesive tape; [0022] FIGS. 9A, 9B, 9C, 9D and 9E are cross sectional views of noise dampers used in the undermentioned comparative tests; and [0023] FIG. 10 is a graph showing the overall noise sound level of a motorcycle rear tire as a function of the running speed. [0024] In the drawings, pneumatic tire 1 according to the present invention comprises: a tread portion 2 with tread edges Te; a pair of axially spaced bead portions 4; a pair of sidewall portions 3 extending between the tread edges Te and the bead portions 4; a carcass 6 extending between the bead portions 4; and a tread reinforcing belt disposed radially outside the carcass in the tread portion. Continue reading... Full patent description for Low noise tire Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Low noise tire patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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